Flywheels are a well known means of storing energy and regulating speed. On vehicles including automobiles a large flywheel is typically mounted to the crankshaft. The flywheel inertia acts to smooth out the pulsating nature of the internal combustion process and prevents speed fluctuations from being transmitted to the transmission and the rest of the drivetrain.
Other uses of flywheels are known as well. For example, a flywheel is used to regulate the grid frequency. When the demand for electricity is high, the generator speed slows reducing the frequency of the supplied AC power as shown in FIG. 1A. At peak demand a flywheel system could provide power, reducing the load on the generator. This keeps the speed of the generator up and maintains the frequency of the AC power. Further, flywheel based auxiliary power units (APU) can be used in power critical applications. In hospitals, if grid power is lost, a flywheel based APU can be used to provide instant power to bridge the gap between grid power loss and diesel generator start up. Similarly, critical computer systems could be kept powered up in the face of power outages.
FIG. 1B demonstrates the use of the flywheel in manufacturing. Machines such as presses use flywheels A to maintain a constant speed under varying loads.
Further, flywheel systems called kinetic energy recovery system (KERS) are being used in certain racing applications including open wheel racing. For example, by recovering energy what would otherwise be wasted in braking the KERS can provide an extra 80 Hp over 6.67 seconds.
Another known system is provided by Flybrid System, Northamptonshire, England as shown in FIG. 2. The system generally comprises a flywheel module A, a CVT module B, a gear train C, and output drive shafts D. The system provides 60 kW and can store 400 kJ of energy in the flywheel with a top speed of 60000 RPM.
Representative of the art is U.S. Pat. No. 3,672,244 which discloses an automotive system employing a high velocity, moderate mass flywheel capable of storing and rapidly dissipating large supplies of kinetic energy coupled with a transmission adapted to permit the smooth release of stored kinetic energy from the flywheel to the vehicle wheels, and a charging means for supplying kinetic energy to the flywheel at relatively low energy levels. The system provides substantial fuel economy and pollution relief through an efficient energy-conversion system.
What is needed is a flywheel hybrid system comprising a flywheel selectively clutched to an internal combustion engine accessory belt drive system. The present invention meets this need.